Chromosomal Microarray, Prenatal, Amniotic Fluid/Chorionic Villus Sampling [A Test in Focus]

Chromosomal Microarray, Prenatal, Amniotic Fluid/Chorionic Villus Sampling is a high-resolution method for detecting copy number changes (gains or losses) across the entire genome in a single assay.

testinfocus-test-info CMAP — Chromosomal Microarray, Prenatal, Amniotic Fluid/Chorionic Villus Sampling

  • Chromosomal abnormalities cause a wide range of disorders associated with birth defects and intellectual disability. Many of these disorders can be diagnosed prenatally by analysis of chorionic villi or amniocytes.
  • Chromosomal microarray (CMA) is a high-resolution method and is sometimes called a molecular karyotype.
  • The American College of Obstetricians and Gynecologists and the Society for Maternal-Fetal Medicine recommend CMA as a replacement for the fetal karyotype in patients with a pregnancy demonstrating 1 or more major structural abnormalities on ultrasound when undergoing invasive prenatal diagnosis. Also, patients requesting invasive diagnostic testing should be offered prenatal CMA.
testinfocus-testutilization How to Use This Test:

Common reasons for performing chromosomal microarray (CMA) for prenatal diagnosis include:

  • Advanced maternal age
  • Abnormal prenatal screen
  • A previous child with a chromosome abnormality
  • Abnormal fetal ultrasound
  • A family history of a chromosome abnormality

Related Algorithms:

  • Copy number variation is found in all individuals, including patients with abnormal phenotypes and normal populations. Therefore, determining the clinical significance of a rare or novel copy number change can be challenging. Parental testing may be necessary to further assess the potential pathogenicity of a copy number change.
  • Identification of regions of excessive homozygosity on a single chromosome could suggest uniparental disomy, which may warrant further clinical investigation when observed on chromosomes with known imprinting disorders.
  • The detection of excessive homozygosity on multiple chromosomes may suggest consanguinity.
  • CMA does not detect balanced chromosome rearrangements such as Robertsonian or other reciprocal translocations, inversions, or balanced insertions.
  • Point mutations, small deletions, or insertions below the resolution of the array are also not detected.
  • Chromosomal Microarray (CMA) using Affymetrix Cytoscan HD
  • Varies: Chorionic Villi or Amniotic Fluid
testinfocus-performance Day(s) and Time(s) Test Performed:

  • Samples processed Monday through Sunday.

Analytic Time:

  • 10 days
Alyssa Frank

Alyssa Frank

Alyssa Frank is a Marketing Segment Manager at Mayo Clinic Laboratories. She leads marketing strategies for product management and specialty testing. Alyssa has worked at Mayo Clinic since 2015.